user-avatar
nhiyenthidao123
2 năm trước
.1/Oxi có những tính chất gì?nêu vai trò của oxi trong quộc sống? 2/sự oxi hóa sự cháy là gì? 3/thế nào là phản ứng hóa hợp. phản ứng phân hủy? 4/nếu chế oxi trong ptn như thế nào?5/nêu thành phần của không khí?6/tính chất và ứng dụng của hiddro? 7/điều chêa H2 trong ptn. thế nào là phản ứng thế? 8/sự phân hủy và tổng hợp của Nước? 9/tính chất của Nước? 10/thế nào là dung dịch dung môi chất tan? 11/thế nào là dung dịch bão hoà? dung dịch chưa bão hòa?12/độ tan của một chất trong nước?13/thế nào là nồng độ phần trăm nồng độ mol của dung dịch? 14/cách pha chế dung dịch
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

Much has been said written about the declining numbers of and disappointing lack of diversity among American college students majoring in engineering. Among the factors cited to explain this phenomenon are the lack of exposure of high school students to the very idea of engineering and the fact that many have insufficient mathematics and science background to gain entrance to engineering school, even if they do identify the profession as a possible career. This is unfortunate, for the ideas of engineering should be integrated into the curricula not only of high schools but also of middle and primary schools. Our children are being done a disservice by not being exposed properly throughout their education to engineering activities identified as such. After all, even pre-school children have the prerequisites in their play for appreciating exactly what engineering is: design, Indeed, design is everywhere around them throughout their school day, even in their before-school and after-school activities. It need only be pointed out to them that they designing something, and therefore being engineering of sorts, in virtually everything that they do 1. the writer of the passage feels strongly that.... A. children should be involved in engineering activities at an early age B. The mathematics and science courses in schools need to be modernized C. University engineering courses ought to be upgraded D. The education of pre-school children is being given too much important 2. The writer points out that children can, at a very early age A. be encouraged to take part in after-school activities B. develop an interested in scientific matters C. make up their minds to study engineering at university D. be influenced by their school environment 3. The writer recognizes the fact that engineering A. is becoming less and less popular as a field of study among university students B. is only suitable for highly intelligent students C. is a complicated subject only suitable for really mature students D. has become one of the most popular fields of study at American universities 4. Among the reasons given in the passage for the decline in the numbers of engineering students is that A. the American schools still follow out - dated curricula curricula B. university entrance requirements are far too demanding C. many of them fail to acquire an adequate knowledge of mathematics and science at high schools. D. it is generally recognized as one of the most difficult of all the courses 5. According to the passage, all school programmes..... A. should be designed to make students aware of the engineering practices and principles B. ought to give priority to sciences C. must encourage children to make creative designs D. Seem to put the emphasis on the need to diversify learning

2018 © Loga - Không Ngừng Sáng Tạo - Bùng Cháy Đam Mê
Loga Team